How our price data is built
Every COMPED price and index figure follows the same rules. Here they are.
Sources
eBay UK sold listings lead. Where a card has too few UK sales, TCGplayer and Cardmarket market trends fill the gap, converted to pounds and clearly labelled as estimates.
Minimum sales
A price counts as sold-backed when it has at least 5 recent UK sales for that exact card and printing. The monthly index only uses cards that meet this in both months it compares.
Outliers and mislabelled sales
Listings for the wrong printing, graded slabs mixed into raw comps, lots and bundles, and prices far from the rest are removed before the middle price is taken.
Printings stay separate
1st Edition, Shadowless, Unlimited, reverse holo and anniversary reprints each have their own price. Collector number and set must both match before a sale is used.
Regions
English, Japanese, Korean and Chinese cards are priced separately.
Checking ourselves
Every price is checked card by card against fresh market evidence, and Digby keeps learning from new UK sales and from human price training. Monthly price index